JP 2000-58514 A discloses plasma processing apparatus of a construction such that a bottomed tray accommodating a substrate is placed on a substrate susceptor that functions as a lower electrode. The substrate is electrostatically attracted to the substrate susceptor indirectly via the tray. A cooling mechanism is provided for the substrate susceptor, and the substrate is cooled by indirect heat conduction to the substrate susceptor via the tray.
JP 2003-197607 A discloses a plasma processing apparatus of a construction such that a bottomed tray accommodating a substrate is placed on a substrate susceptor with a vicinity of an outer peripheral edge of the substrate being pressurized against the substrate susceptor side by a clamp ring, whereby the substrate is fixed to the substrate susceptor. A flow passage that penetrates the tray and reaches a lower surface of the substrate is provided such that the back surface of the substrate is cooled by a coolant gas supplied via the flow passage.
However, in the plasma processing apparatus disclosed in the former publication, the substrate is electrostatically attracted indirectly to the substrate susceptor via the tray and merely cooled by indirect heat conduction to the substrate susceptor via the tray. Therefore, the substrate cannot be efficiently cooled.
On the other hand, in the plasma processing apparatus disclosed in the latter publication, the state of the plasma tends to become unstable particularly at the vicinity of the outer peripheral edge of the substrate where the clamp ring exists. This results in that the processing cannot be uniformed at a center portion and the vicinity of the outer peripheral edge of the substrate. For example, in the case of dry etching, no etching pattern can be formed at the vicinity of the outer peripheral edge of the substrate where the clamp ring exists.
Further, in the conventionally proposed plasma processing apparatuses adopting the system where the tray accommodating the substrate is placed on the substrate susceptor, including those disclosed in the above-mentioned two publications, positioning accuracy of the substrate with respect to the substrate susceptor is not sufficiently considered. However, the positioning accuracy of the substrate with respect to the substrate susceptor is important particularly in achieving batch processing of a plurality of substrates accommodated on one tray.